Usually, a PDP shows high power consumption due to its driving characteristics. Therefore, control of its power consumption is needed according to a required load of a displayed frame. For the control of the power consumption, a power level is automatically controlled to remain under a limit.
According to the prior art, such automatic power control is only applied to a power source regarding generation of sustain pulses but not to a power source regarding generation of address data. Accordingly, power consumption regarding generation of address data has remained at a high level.
FIG. 1 illustrates image data in a full-white state. In a full-white state where every image data segment will have the value of “1”, almost no fluctuation in data is introduced throughout address electrodes, and pulse switching also remains at its minimum. In addition, charging/discharging reactive power also remains small since power consumption proportionally increases with the number of times of switching. A driving signal for such a full-white state may have a waveform as shown in FIG. 2. As shown in FIG. 2, in a full-white state, it is only required to switch once for column 10 in FIG. 1.
However, image data can be of a dot-pattern as illustrated in FIG. 3 wherein image data repeatedly alternates between 1 and 0. Accordingly, a significant amout of switching is required, for example, for column 20. A corresponding driving signal may have a waveform shown in FIG. 4. As shown in FIG. 4, in a dot-pattern, data fluctuation and pulse switching will occur. As a result, power consumption increases.
As can be seen from the above description, power consumption increases as the number of different pixels between a previous line and a current line increases and also because of the increase in switching.